gsm48_decode_bcd_number2(): fix output truncation
Thanks to the new unit test for BCD number encoding / decoding, it was
discovered that gsm48_decode_bcd_number2() does not properly handle
encoded LV if the output buffer size is equal to the original MSISDN
length + 1 (\0-terminator): one digit is lost.
For example, decoding of 15-digit long MSISDN to a buffer of size
16 (15 digits + 1 for \0) would give us only 14 digits.
The problem was that 'output_len' was being decremented before
checking the remaining buffer length and writing a digit to it.
As a result, the maximum length was always one byte shorter.
Change-Id: I61d49387fedbf7b238e21540a5eff22f6861e27a
Fixes: OS#4025
diff --git a/tests/gsm0408/gsm0408_test.ok b/tests/gsm0408/gsm0408_test.ok
index 2441b2b..3938e87 100644
--- a/tests/gsm0408/gsm0408_test.ok
+++ b/tests/gsm0408/gsm0408_test.ok
@@ -167,14 +167,14 @@
- Actual: (rc=9) '0821436587092143f5'
- Decoding HEX (buffer limit=16) '0821436587092143f5'...
- Expected: (rc=0) '123456789012345'
- - Actual: (rc=0) '12345678901234'
+ - Actual: (rc=0) '123456789012345'
- Running test: to be truncated 20-digit MSISDN
- Encoding ASCII (buffer limit=9) '12345678901234567890'...
- Expected: (rc=-5) ''
- Actual: (rc=-5) ''
- Decoding HEX (buffer limit=16) '0a21436587092143658709'...
- Expected: (rc=0) '123456789012345'
- - Actual: (rc=0) '12345678901234'
+ - Actual: (rc=0) '123456789012345'
- Running test: LV incorrect length
- Decoding HEX (buffer limit=0) '05214365'...
- Expected: (rc=-5) '(none)'